The Effect of Spherical Hub-Nose Position on Pressure Drop in an Oscillating Water Column System for Wave Energy Conversion

Keywords

Wave energy conversion, OWC, Hub-nose position, CFD.

Abstract

This paper presents an investigation of pressure drop
which occurred in an OWC system as the effect of
spherical hub-nose position in an annular duct. Study has
been carried out by means of computational fluid
dynamics (CFD) under steady flow conditions for several
hub-nose positions.
As a result, the CFD analysis has been able to reveal
the characteristic of pressure drop which was relatively
reasonable. It was found that the hub-nose position
influenced pressure drop occurred in the OWC system. In
this study, the highest value of the pressure drop occurred
when the hub-nose is at the position of 0.0 m relatively to
the end of converging cone. The pressure drop tends to
decrease when the hub-nose position move away from the
end of converging cone. The lowest value occurred at the
position of -0.5 m in which the hub needed to be extended
so that the hub-nose is inside the converging cone.
Although the change of pressure drop due to the effect of
the hub-nose position is numerically small, this
phenomenon needs to be considered in the design process
of the OWC system. The consideration is related to the
operational condition of the system which is at low–
pressure pneumatic power, and actually the pressure drop
reduces the potency of energy that will be converted by
the air turbine.